A common cause for catastrophic failure in a magnetic disk storage system is due to the collection of debris on the slider/head assembly. Two factors contributing to these failures are: PA1 a) disk liquid lubricant provides a sticky medium for debris accumulation; and PA1 b) electrostatic charge on the slider assembly generated by friction attracts and accumulates debris. A method for reducing electrostatic charge build-up uses a conductive coating on a surface area of the slider. By providing a conducting path to the metallic disk on which the recording medium is applied, the triboelectrically generated charge on the slider is allowed to bleed-off. Providing an additional overcoat of a solid self-lubricant, and forming a wedge-shaped slider load-bearing surface for deflection of surface debris, results in the reduction of both failure causes.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A disk drive, comprising: a disk; a slider/head assembly including a slider that includes an electrically conductive coating, and a head that writes data to and reads data from the disk, wherein the electrically conductive coating has a tapered thickness beginning in proximity to the head and increasing in thickness towards a leading edge of the slider that faces a relative motion of the disk; and an electrically conductive discharge path connected to the electrically conductive coating so as to reduce electrostatic charge that accumulates on the slider/head assembly due to contact between the slider/head assembly and the disk.
2. The disk drive of claim 1, wherein the tapered thickness has a uniform taper.
3. The disk drive of claim 1, wherein the slider includes a trailing edge that faces away from the relative motion of the disk, and the tapered thickness extends across a majority of a distance between the leading and trailing edges.
4. The disk drive of claim 1, wherein the slider includes a load-bearing surface, and the tapered thickness extends across substantially all of the load-bearing surface.
5. The disk drive of claim 1, wherein the electrically conductive coating includes a uniform thickness between and adjacent to the leading edge and the tapered thickness, and a length of the uniform thickness is less than a length of the tapered thickness.
6. A disk drive, comprising: a disk; a slider/head assembly including a slider that includes an electrically conductive coating, a load-bearing surface facing the disk, and a nonload-bearing surface that faces a relative motion of the disk, wherein the electrically conductive coating covers substantially all of the nonload-bearing surface without covering substantially all of the load-bearing surface; and a head that writes data to and reads data from the disk; and an electrically conductive discharge path connected to the electrically conductive coating so as to reduce electrostatic charge that accumulates on the slider/head assembly due to contact between the slider/head assembly and the disk.
7. The disk drive of claim 6, wherein the slider includes a leading edge that faces the relative motion of the disk, and the nonload-bearing surface is between the leading edge and the load-bearing surface.
8. The disk drive of claim 6, wherein the load-bearing and nonload-bearing surfaces are contiguous with one another.
9. The disk drive of claim 6, wherein the electrically conductive coating covers substantially none of the load-bearing surface.
10. The disk drive of claim 9, wherein the slider includes a leading edge that faces the relative motion of the disk, and the nonload-bearing surface is between and contiguous with the leading edge and the load-bearing surface.
11. A disk drive, comprising: a disk; a slider/head assembly including a slider that includes an electrically conductive coating alloyed to an electrically non-conductive base, wherein the electrically conductive coating is an alloy of an electrically conductive material and the electrically non-conductive base, the electrically conductive material includes titanium and the electrically non-conductive base includes alumina, and a head that writes data to and reads data from the disk; and an electrically conductive discharge path connected to the electrically conductive coating so as to reduce electrostatic charge that accumulates on the slider/head assembly due to contact between the slider/head assembly and the disk.
12. A disk drive, comprising: a disk; a slider/head assembly including a slider that includes an electrically conductive coating alloyed to an electrically non-conductive base, wherein the electrically conductive coating is an alloy of an electrically conductive material and the electrically non-conductive base, and a head that writes data to and reads data from the disk; and an electrically conductive discharge path connected to the electrically conductive coating so as to reduce electrostatic charge that accumulates on the slider/head assembly due to contact between the slider/head assembly and the disk.
13. The disk drive of claim 12, wherein the electrically conductive material is titanium.
14. The disk drive of claim 12, wherein the electrically non-conductive base is alumina.
15. The disk drive of claim 12, wherein the electrically conductive coating is titanium alloyed with alumina.
16. A disk drive, comprising: a disk; a spindle mechanically coupled to the disk for rotating the disk; a slider/head assembly including a slider that includes an electrically conductive coating, and a head that writes data to and reads data from the disk; and an electrically conductive discharge path connected to the electrically conductive coating and the disk so as to reduce electrostatic charge that accumulates on the slider/head assembly due to contact between the slider/head assembly and the disk, wherein the discharge path excludes the spindle.
17. The disk drive of claim 16, wherein the discharge path includes a brush.
18. The disk drive of claim 16, wherein the discharge path includes a slip-ring contact.
19. The disk drive of claim 16, wherein the discharge path includes a brush that provides a slip-ring contact.
20. The disk drive of claim 16, wherein the discharge path provides a direct connection between the electrically conductive coating and the disk.
21. A disk drive, comprising: a disk; a spindle mechanically coupled to the disk for rotating the disk; a slider/head assembly including a slider that includes an electrically conductive coating, and a head that writes data to and reads data from the disk; and an electrically conductive discharge path connected to the electrically conductive coating so as to reduce electrostatic charge that accumulates on the slider/head assembly due to contact between the slider/head assembly and the disk, wherein the discharge path includes a brush external to the spindle.
22. The disk drive of claim 21, wherein the brush provides a slip-ring contact.
23. The disk drive of claim 21, wherein the brush contacts the disk.
24. The disk drive of claim 21, wherein the brush contacts the spindle.
25. The disk drive of claim 21, wherein the discharge path includes the brush, the spindle and the disk.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
October 12, 1999
November 27, 2001
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